As shown in patent documents 1 and 2, a conventional transmission is provided with a belt-type continuously variable transmission mechanism (CVT) including a primary pulley installed on a drive shaft, a secondary pulley installed on a driven shaft arranged parallel to the drive shaft at a predetermined distance and an endless V-belt wound between the primary pulley and the secondary pulley.
The transmission described in patent document 2 includes a power transmission switching mechanism (sub-transmission mechanism) for switching transmission routes of a driving force input to the continuously variable transmission mechanism (CVT) or a driving force output from the continuously variable transmission. This power transmission switching mechanism is structured by a jaw clutch, a synchromesh mechanism and other components, and provided with a hub fixed on the rotation shaft, a sleeve fit to the hub via a spline groove to slide axially and a gear for transmitting a driving force by engaging with the hub via the sleeve.